No Answer on all calls

The flight that I booked for my husband was through Travelstart. Everything was good untill we found out from his Company that the flight returning to Bamako from OR Thambo via Nairobi was cancelled. I tried to change the return ticket with Travelstart 3 days in a row. I used 2 numbers, holding on for between 10 to 20 minutes and never got through to their call centre. I tried to change the booking with Kulula.com (they answered after the second ring). They could not change it as it was not done by them allthough it was on one of their flights. They try to phone Travelstart while I was on the other line but also was unsuccesfull. At long last I found a new number for Travelstart for urgent bookings or changes. I phoned them again and again was unsuccesfull after 20 minutes I gave up. I sent them a urgent e-mail requesting the alteration on my booking. The price they gave me, was more than the original amount I paid for the ticket. This will be the last time that I made use of them, I think they are the worst call centre I've ever encounted, not for their poor service, but for NO SERVICE.